:root {
  --color-canvas: #F9FAFC;
  --color-panel: #FFFFFF;
  --color-panel-soft: #F1F4F8;
  --color-border: #D5DCE6;
  --color-border-strong: #B5C0CF;
  --color-accent: #087CEB;
  --color-accent-deep: #075AB0;
  --color-ink: #0B1733;
  --color-ink-muted: #526071;
  --color-success: #19A865;
  --color-warning: #D98B00;
  --color-error: #D74747;
  --color-terminal: #08152D;
  --color-terminal-bar: #0D1D39;
  --color-terminal-border: #263B5D;
  --color-terminal-text: #D9E5F4;
  --color-terminal-muted: #8292AA;
  --color-terminal-blue: #65AEF5;
  --color-terminal-green: #57D393;
  --color-flag-white: #FFFFFF;
  --color-flag-red: #D74747;
  --color-flag-red-deep: #B82636;
  --color-flag-blue: #244C91;
  --color-flag-blue-deep: #183B75;
  --color-flag-black: #172033;
  --color-flag-yellow: #F0C640;
  --shadow-soft: 0 3px 12px rgba(11, 23, 51, 0.08);
  --shadow-panel: 0 14px 30px rgba(11, 23, 51, 0.10);
  --shadow-deep: 0 22px 42px rgba(11, 23, 51, 0.16);
  --wash-accent: rgba(8, 124, 235, 0.08);
  --border-accent: rgba(8, 124, 235, 0.24);
  --terminal-rule: rgba(213, 220, 230, 0.14);
  --font-display: "Inter", "Noto Sans SC", "Noto Sans JP", "Noto Sans KR", system-ui, sans-serif;
  --font-body: "Inter", "Noto Sans SC", "Noto Sans JP", "Noto Sans KR", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", Consolas, monospace;
  --radius-xs: 4px;
  --radius-sm: 7px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-pill: 999px;
  --wrap-max: 1344px;
  --reading-max: 48rem;
  --gutter: 32px;
  --header-height: 84px;
  --toc-offset: 76px;
  --space-section: 96px;
  --transition-fast: 160ms ease;
  --transition-reveal: 560ms cubic-bezier(.2, .75, .25, 1);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: var(--color-canvas);
}

html.nav-open {
  overflow: hidden;
}

body {
  min-width: 0;
  min-height: 100%;
  margin: 0;
  overflow-x: clip;
  background: var(--color-canvas);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  text-rendering: optimizeLegibility;
}

main,
section,
article,
aside,
header,
footer,
nav,
div {
  min-width: 0;
}

img,
svg,
video {
  display: block;
  max-width: 100%;
}

img {
  height: auto;
}

button,
input,
select,
textarea {
  color: inherit;
  font: inherit;
}

button,
summary {
  cursor: pointer;
}

a {
  color: inherit;
  text-decoration: none;
}

p,
ul,
ol,
blockquote,
pre,
table {
  margin-top: 0;
}

p {
  margin-bottom: 1.15em;
}

ul,
ol {
  padding-left: 1.4em;
}

code,
kbd,
samp,
pre {
  font-family: var(--font-mono);
}

:not(pre) > code {
  padding: 0.1em 0.35em;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xs);
  background: var(--color-panel-soft);
  overflow-wrap: anywhere;
}

pre {
  max-width: 100%;
  padding: 18px;
  overflow-x: auto;
  border: 1px solid var(--color-terminal-border);
  border-radius: var(--radius-sm);
  background: var(--color-terminal);
  color: var(--color-terminal-text);
  line-height: 1.65;
  -webkit-overflow-scrolling: touch;
}

pre code {
  white-space: pre;
  overflow-wrap: normal;
}

hr {
  height: 1px;
  margin: 36px 0;
  border: 0;
  background: var(--color-border);
}

::selection {
  background: var(--color-accent);
  color: var(--color-panel);
}

:focus-visible {
  outline: 3px solid var(--border-accent);
  outline-offset: 3px;
}

.wrap {
  width: 100%;
  max-width: calc(var(--wrap-max) + (var(--gutter) * 2));
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.reading-wrap {
  width: 100%;
  max-width: calc(var(--reading-max) + (var(--gutter) * 2));
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  padding-top: var(--space-section);
  padding-bottom: var(--space-section);
}

.section-soft {
  background: var(--color-panel-soft);
}

.section-head {
  max-width: 780px;
  margin-bottom: 38px;
}

.kicker {
  margin: 0 0 12px;
  color: var(--color-accent-deep);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

h1,
h2,
h3,
h4 {
  margin-top: 0;
  color: var(--color-ink);
  font-family: var(--font-display);
  text-wrap: balance;
}

h1,
.hero-title {
  margin-bottom: 22px;
  font-size: clamp(52px, 5.2vw, 68px);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

h2 {
  margin-bottom: 18px;
  font-size: clamp(34px, 4vw, 52px);
  font-weight: 880;
  line-height: 1.14;
  letter-spacing: -0.018em;
}

h3 {
  margin-bottom: 12px;
  font-size: clamp(22px, 2.3vw, 30px);
  font-weight: 820;
  line-height: 1.25;
}

h4 {
  margin-bottom: 8px;
  font-size: 18px;
  font-weight: 800;
  line-height: 1.35;
}

.no-break {
  white-space: nowrap;
}

.accent-text {
  color: var(--color-accent);
}

.lead {
  max-width: 720px;
  color: var(--color-ink-muted);
  font-size: clamp(18px, 2vw, 21px);
  line-height: 1.7;
}

.muted {
  color: var(--color-ink-muted);
}

.mono {
  font-family: var(--font-mono);
}

.button {
  min-height: 48px;
  padding: 0 22px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-weight: 800;
  line-height: 1.2;
  white-space: nowrap;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast), transform var(--transition-fast);
}

.button:hover {
  transform: translateY(-1px);
}

.button:active {
  transform: translateY(0);
}

.button svg {
  width: 17px;
  height: 17px;
  flex: 0 0 auto;
}

.button-primary {
  border-color: var(--color-accent);
  background: var(--color-accent);
  color: var(--color-panel);
  box-shadow: 0 7px 16px var(--border-accent);
}

.button-primary:hover {
  border-color: var(--color-accent-deep);
  background: var(--color-accent-deep);
}

.button-secondary {
  border-color: var(--color-border-strong);
  background: var(--color-panel);
  color: var(--color-ink);
  box-shadow: var(--shadow-soft);
}

.button-secondary:hover {
  border-color: var(--color-accent);
  color: var(--color-accent-deep);
}

.button-quiet {
  border-color: var(--color-border);
  background: var(--color-panel-soft);
  color: var(--color-ink-muted);
}

.button[disabled],
.button.is-disabled {
  cursor: not-allowed;
  opacity: 0.55;
  transform: none;
}

.badge {
  max-width: 100%;
  min-height: 28px;
  padding: 4px 9px;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  overflow: hidden;
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-pill);
  background: var(--color-panel);
  color: var(--color-accent-deep);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 750;
  line-height: 1.3;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.status-dot {
  width: 8px;
  height: 8px;
  flex: 0 0 auto;
  border-radius: var(--radius-pill);
  background: var(--color-success);
}

.panel,
.card {
  min-width: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-panel);
}

.card {
  padding: 26px;
  box-shadow: var(--shadow-soft);
}

.panel-soft {
  background: var(--color-panel-soft);
}

.reveal {
  transition: opacity var(--transition-reveal), transform var(--transition-reveal);
}

.reveal.pending {
  opacity: 0;
  transform: translateY(16px);
}

.reveal.shown {
  opacity: 1;
  transform: none;
}

.site-header {
  position: relative;
  z-index: 80;
  height: var(--header-height);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-canvas);
}

.header-inner {
  width: 100%;
  max-width: calc(var(--wrap-max) + (var(--gutter) * 2));
  height: 100%;
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  gap: 20px;
}

.site-brand {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  gap: 10px;
}

.site-brand img {
  width: 34px;
  height: 39px;
  object-fit: contain;
}

.brand-copy {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  white-space: nowrap;
}

.brand-latin {
  font-family: var(--font-display);
  font-size: 21px;
  font-weight: 900;
  letter-spacing: -0.02em;
}

.brand-local {
  color: var(--color-ink-muted);
  font-size: 13px;
  font-weight: 650;
}

.desktop-nav {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 2px;
}

.nav-link {
  min-height: 40px;
  padding: 0 8px;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  border-radius: var(--radius-xs);
  color: var(--color-ink-muted);
  font-size: 13px;
  font-weight: 680;
  white-space: nowrap;
}

.nav-link svg {
  width: 15px;
  height: 15px;
  flex: 0 0 auto;
}

.nav-link:hover,
.nav-link[aria-current="page"] {
  background: var(--wash-accent);
  color: var(--color-accent-deep);
}

.header-tools {
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  gap: 7px;
}

.language-menu {
  position: relative;
}

.language-trigger {
  min-height: 40px;
  padding: 0 8px;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  border: 0;
  border-radius: var(--radius-xs);
  background: transparent;
  color: var(--color-ink-muted);
  font-size: 12px;
  font-weight: 700;
}

.language-trigger svg {
  width: 15px;
  height: 15px;
  flex: 0 0 auto;
}

.language-list {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  z-index: 95;
  width: 172px;
  padding: 6px;
  display: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-panel);
  box-shadow: var(--shadow-panel);
}

.language-menu.is-open .language-list {
  display: grid;
}

.language-list a {
  min-height: 40px;
  padding: 8px 10px;
  display: flex;
  align-items: center;
  border-radius: var(--radius-xs);
  color: var(--color-ink-muted);
  font-size: 13px;
  font-weight: 650;
}

.language-list a:hover,
.language-list a[aria-current="true"] {
  background: var(--wash-accent);
  color: var(--color-accent-deep);
}

.login-button {
  min-width: 72px;
  min-height: 40px;
  padding: 0 17px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius-sm);
  background: var(--color-panel);
  color: var(--color-ink);
  font-size: 14px;
  font-weight: 780;
  box-shadow: 0 1px 2px rgba(11, 23, 51, 0.08);
}

.login-button:hover {
  border-color: var(--color-accent);
  color: var(--color-accent-deep);
}

.menu-button {
  min-width: 44px;
  min-height: 44px;
  padding: 0;
  display: none;
  place-items: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-panel);
}

.menu-button svg {
  width: 21px;
  height: 21px;
}

.mobile-nav {
  position: absolute;
  top: 100%;
  right: 0;
  left: 0;
  z-index: 92;
  max-height: calc(100dvh - var(--header-height));
  padding: 12px var(--gutter) 20px;
  display: none;
  overflow-y: auto;
  overscroll-behavior: contain;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-panel);
  box-shadow: var(--shadow-panel);
}

.mobile-nav.is-open {
  display: block;
}

.mobile-nav .nav-link,
.mobile-language-links a {
  width: 100%;
  min-height: 48px;
  padding: 11px 12px;
  display: flex;
}

.mobile-language-links {
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px solid var(--color-border);
}

.mobile-language-links a {
  align-items: center;
  border-radius: var(--radius-xs);
  color: var(--color-ink-muted);
  font-size: 14px;
  font-weight: 650;
}

.mobile-language-links a[aria-current="true"] {
  background: var(--wash-accent);
  color: var(--color-accent-deep);
}

.nav-veil {
  position: fixed;
  inset: var(--header-height) 0 0;
  z-index: 70;
  display: none;
  border: 0;
  background: rgba(11, 23, 51, 0.16);
}

.nav-veil.is-open {
  display: block;
}

.site-footer {
  border-top: 1px solid var(--color-border);
  background: var(--color-panel);
}

.footer-main {
  padding-top: 64px;
  padding-bottom: 48px;
  display: grid;
  grid-template-columns: 1.3fr 1fr 1.2fr 1fr;
  gap: 44px;
}

.footer-brand p {
  max-width: 330px;
  color: var(--color-ink-muted);
  font-size: 14px;
}

.footer-title {
  margin: 0 0 14px;
  font-size: 13px;
  font-weight: 820;
}

.footer-links {
  display: grid;
  gap: 8px;
}

.footer-links a {
  width: fit-content;
  color: var(--color-ink-muted);
  font-size: 13px;
}

.footer-links a:hover {
  color: var(--color-accent-deep);
}

.footer-bottom {
  padding-top: 20px;
  padding-bottom: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  border-top: 1px solid var(--color-border);
  color: var(--color-ink-muted);
  font-size: 12px;
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.prose {
  color: var(--color-ink);
}

.prose h2,
.prose h3 {
  scroll-margin-top: var(--toc-offset);
}

.prose h2 {
  margin-top: 2.1em;
}

.prose h3 {
  margin-top: 1.65em;
}

.prose a {
  color: var(--color-accent-deep);
  text-decoration: underline;
  text-underline-offset: 0.18em;
}

.prose img {
  margin: 30px auto;
}

.prose blockquote {
  margin-inline: 0;
}

body:has(.toc-tabs) section[id] {
  scroll-margin-top: var(--toc-offset);
}

.tilt,
.tilt-card {
  transform: rotate(-0.35deg);
}

@media (max-width: 1240px) {
  :root {
    --gutter: 20px;
  }

  .header-inner {
    gap: 12px;
  }

  .nav-link {
    padding-inline: 6px;
    font-size: 12px;
  }

  .brand-local {
    display: none;
  }
}

@media (max-width: 1040px) {
  .desktop-nav,
  .language-menu {
    display: none;
  }

  .header-tools {
    margin-left: auto;
  }

  .menu-button {
    display: grid;
  }

  .footer-main {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 70px;
    --space-section: 68px;
  }

  h1,
  .hero-title {
    font-size: clamp(32px, 9.7vw, 40px);
    line-height: 1.12;
    letter-spacing: -0.015em;
  }

  h2 {
    font-size: clamp(28px, 8vw, 38px);
  }

  .section-head {
    margin-bottom: 28px;
  }

  .login-button {
    min-width: 62px;
    padding-inline: 12px;
  }

  .footer-bottom {
    align-items: flex-start;
    flex-direction: column;
  }

  .absolute-decoration,
  .decorative-caption {
    display: none;
  }
}

@media (max-width: 640px) {
  :root {
    --gutter: 16px;
  }

  body {
    font-size: 15px;
  }

  .header-inner {
    padding-inline: var(--gutter);
  }

  .site-brand img {
    width: 29px;
    height: 34px;
  }

  .brand-latin {
    font-size: 18px;
  }

  .button {
    max-width: 100%;
    white-space: normal;
  }

  .footer-main {
    grid-template-columns: minmax(0, 1fr);
    gap: 30px;
  }

  .tilt,
  .tilt-card {
    transform: none;
  }

  .card {
    padding: 20px;
  }
}

@media (max-width: 390px) {
  .brand-copy {
    display: none;
  }

  .header-tools {
    gap: 5px;
  }

  .login-button {
    min-width: 58px;
    padding-inline: 10px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }

  .reveal,
  .reveal.pending {
    opacity: 1;
    transform: none;
  }
}